I would not worry too much, our generation were raised on tin spoons and latex and we are o.k. (I think). If it is something that is really gonna worry you then throw them all out and use the same plates and bowels etc that you use, my middle one is nearly 3 and he has been using our crockery since he got past the age of throwing it on the floor. Regards a cup or beaker just buy a new one!
So, how do I know what hard plastic products are safe? In Canada they've just banned a substance called 'bisphenol A" saying it is really harmful. Apparently, its in plastic bottles, cups, etc.. In the meantime, in the last 4 years, I've collected a huge drawer full of plastic cups, bowls, etc.. Now, I don't know which to use and which to throw out. Anyone know how to tell?